This invention relates to a portable retroreflectometer for measuring the optical characteristics in multiple-angle point and annular geometry of retroreflective materials as typically used to male highway signs and safety markers. Unlike conventional reflection plane mirrors which reflect incident light back toward the source only if the incident light beam is perpendicular to the mirror surface, retroreflective materials reflect a non-perpendicular incident beam back toward the source. Elevated highway signs and markers illuminated by vehicle headlights can thus be seen and understood by a driver (whose eyes are positioned above the illuminating headlights) of the vehicle. The retroreflectometer enables verification of the optical characteristics of new signs and markers, and also the level of degradation of retroreflectivity of a worn, weathered, dirty, or otherwise partially obscured sign or marker.